you need to be prepaired as it may not be the bulb
With boats as old as ours, mine is a 1979 Hunter 30', you may find as I did when I replaced my burned out anchor light, the the wire connecting to the socket had rusted off the post.In my case, I found it easier to replace the fixture, as the old fixture was beyound repair.Good luck with your project.Ians/v Meant to Be